Power steering mechanism



Oct. 14, 1947. H, H K 2,429,185

POWER STEERING MECHANI SM Filed Dec. 9, 1944 MIN IN V EN TOR.

BY I 1" Q A TTORNEY -motive vehicle. an automotive vehicle. One of said wheels ll simple and compact power means, cooperating erated pitman arm-l2 is plvotally connected at with manually operated means, for actuating one of its ends i l to one end of the drag link the front wheels of an automotive vehicle, said said arm being pivotally mounted upon a pin I6 means for actuating the front wheels of an auto- The casing and power element together conating said wheels comes into play after, but only by the reference numeral 26.

the operation of said motor and the steering face of the motor casing ii. A P 33 cu ed to junction with the accompanying drawing illus- 45 duct 46.

manually operated steering mechanism constitutand steering wheel of the vehicle, said force Patented Gail M, 94?

rowan s'rshnmc MECHANISM Henry D. Hukill, South Bend Ind., asslgnor to Bendix Aviation Corporation, South Bend, Ind.,

' a corporation of Delaware Application December 9, 1944, Serial No. 567,461

4 Claims. (Cl. 180-793) This invention relates in general to steering vention, a drag link In i connected to the usual mechanism and more particularly to steering steering mechanism, not shown. for effecting mechanism for the dirigible wheels of an autothe steering movement of the front wheels of It is an object of my invention to provide a 5 is shown inFigure 1. Apower and manually oppower mean including a double-acting pressure fixedly connected to the chassis of the vehicle or a differential operated motor controlled by a folpart secured thereto. low-up valve; it is a further object of my inven- The power means for actuating the drag link tion to combine, with this follow-up valve,'soi0 comprises a box shapedtwo-part casing it called feel means for advising the driver of the .housing a two-part power element I8. As disvehicle just when the operation of the aforemenclosed in Figure 2 the ball shaped endportion tioned power means is initiated. iii of a lever 22 is mounted between the two parts Yet another object of my invention is to proof the power element l8, said lever being rulvide a combined power and manually operated c llmed at 24 upo P secured to the Casingmotive vehicle, said means being so constructed .stitute a pressu t al operated motor in-' and so operative that the power means for actu- 2 dicated as a whole in the figures of the drawin after, the resistance to movement of said wheels The motor 26 is controlled by a valve mechaexceeds a certain factor. nism 28 preferably detachably mounted upon the A further object of my invention is to provide, 11101101, all a disclosed n F u e This valve in amanually and power operated steering mechmechanism includes a casing member ll p rted anism for an automotive vehicle, force transmitat 32 to receive a conduit 34 which conduit is ting mean interconnecting th drag link-of t preferably connected to a source of air pressure, steering mechanism of said vehicle, the power for example storage a t shown. A c pelement of a pressure differential operated moshaped valve member 6, preferably rectan ular tor, a part of the valve mechanism for controlling in O s slldably mounted on the Outer wheel or said vehicle, said force transmitting the inner Surface of the valve member 36 means including two springs, one or the other of tends through o end of an angula p 1110?, said springs being first operative, under normal as in the motor cas l d du t to driving conditions, to make possible a manual 35 vent the interior of the valve to the atmosphere. operation of the steering mechanism and then A duct 42 within the motor casing serves to conoperative, by virtue of its expansion, to make nect a compartment 44 of the motor 26 with the possible a power operation of the steering mechsuperatmospheric pressure source when the valve anism when an appreciable force is necessary to member 36 is moved to the right, Figure 2, to turn the steering wheels. 40 uncover one end of said duct 42; and a duct Other objects of the invention and desirable d6 serves to connect a compartment 48 of the det il of construction of p r W l c me 4 motor 26 with said superatmospheric pressure parent from the following detailed description of source when the valve member. 38 is moved to one embodiment of the invention, taken in conthe left, Figure 2, to uncover one end of said trating said embodiment, in which: Describing now the force transmitting means Figure 1 is a diagrammaticview disclosing the interconnecting the power element I8 of the principal elements of the combined power and motor, the valve member 36, the drag link "I,

ing my invention;- and 5 transmitting means comprises suitable steering Figure 2 is a sectional view of the principal wheel operated gearing housed within a casing 52,

parts of the steering mechanism disclosed in said gearing serving to rotate a shaft 54 either Figure 1. clockwise or counterclockwise depending of Referring now to the two figures of the drawcourse, upon the direction of rotation of the steering disclosing a preferred embodiment of my in- 55 ing wheel. To the shaft 54 there are keyed cranks therein a spring 10.

central portion of-a floating lever 66. The means fortconnecting the crank 56 and pitinan arm comprises a link 62 having a spring 64 incorporated therein; and a link 66 constitutes the means for interconnecting the lever 60 and the crank 58. The crank 58 and pitman arm are interconnected by a link 66 having incorporated A link H, pivotally connected to the pitman arm I! and the levers 60 and-22, and a link 12 interconnecting the pin 88 and the upper end of the lever 60, completes the aforementioned force transmitting means interconnecting the vaive, the motor, the steering wheel and the drag link,

Describing now the operation of the combined manually and power operated mechanism constituting my invention, to effect a steering movement of the dirigible wheels i i the steering wheel may be rotated to the right; and this operation serves say to rotate the shaft 54 clockwise. Now the clockwise rotation of the shaft 58 results in a corresponding angular-movement of the cranks 56 and 58: and this operation, through the intermediary of the link 68 and spring 10 which are placed in tension, serves to rotate the pitman arm or lever 12 in a clockwise direction about its pivot I 6. In this operation the spring 64 does not yield, that is does not expand.

The drag link I0 is thus moved to the left, Figure 2, to effect a steering movement of the wheels H. In this operation the floating lever 60 rotates' about its pivotal connection with the link 12, the latter being connected with the aforementioned valve operating pin 38. A spring It, inter osed between the valve member 36 and a portion of the valve casing 30, is of such strength as to insure this operation, that is insure the immobility of the valve 36 during the first increment of movement of the drag link Ill. Now it is to be particularly noted that this initial movement of the drag link is effected solely by the physical effort of the driver there being no operation of the valve to effect an energize,- tion of the motor 26.

To effect the opposite turning movement of the front' wheels ii the steering wheel is, of course, rotated in the other direction; and this operation serves to rotate the shaft 54 counterclockwise and the cranks 56 and 56 keyed thereto. The drag link I0 is thus bodily moved to the right, Figure 2, to efiect a steering movement of the front wheels, it being noted that a spring 18, a duplicate of the aforementioned spring '14, serves, during this operation, to insure a fulcruming of the lever 60 at its connection with the link 12.

Now with all normal driving of the vehicle, say near the crown of a paved or cement highway, the steering movement of the front wheels is effected asdescribed above, that is solely by the physical effort of the driver. However when an unsual amount of force is necessary to turn the vehicle, say when the vehicle is parked in muddy ground, then it is necessary to bring into play the power means of my invention; and this is effected when the force necessary to turn the steering wheels exceeds the force necessary to elongate either the spring 64 or the spring 70 depending, of course, on the steering operation being efiected. Should such a steering force be necessary to turn the wheels then with one of the turning operations the spring 66 is elongated, the pitman arm I! remaining stationary. With this operation the crank 58, which is rotated counterclockwise, serves to move the link 66; and this operation serves to rotate the lever 60 about its pivotal connection with the link 1| thereby opening the valve 36. To make this operation possible, the spring 18 is of such a strength and the remainder of the force transmitting means is so constructed, that said spring will be collapsed by a force which is equal to or substantially equal to the force necessary to elongate the spring 64. It is. of course, also true that when the spring 10 is elongated the spring 14 is collapsed to effect an opening of the valve 36.

Now with the opening of the valve, it being assumed that the valve member 36 is moved to the right to uncover the duct 52 the motor 26 is energized. Describing this operation, when the duct 42 is uncovered, the motor compartment 45 is connected with the source of air pressure thereby efiecting a movement of the power element I8 to the left, Figure 2. The motor compartment 48 is at this time vented to the atmosphere via, the ducts A0 and H6, accordingly, the above described power operation is effected; for the power element is then subjected to a differential of pressures. Now the movement of the power element I8 to the left serves to rotate the lever 22 counterclockwise thereby bodily moving the link H; and this operation serves, through the intermediary of the angularly moved pitinan arm, to effect a movement of the drag link In to the right.

It is apparent, therefore, that when the spring 54 is elongated by a counterclockwise rotation of the crank 56, the operation of the power means is initiated to effect a rightward movement of the drag link Ill.

If the driver wishes to supplement the force exerted by the motor 26 with his own physical efiort he can, in the above described operation, do so by rotating crank 58 far enough to bring a pin into contact with a wall of an enlarged portion '19 of the pitman arm l2. The pin 80, which is mounted in the link 66, extends through an opening in said enlarged portion 19. It is apparent, therefore, that after the lost motion between the pin 80 and the portion 19 is taken up, then continued rotation of the crank 58 will effect a manual loading of the drag link i0 which loading supplements the then existing power loading of said link.

The driver may eflect a power operation of the wheels II in a succession of steps and to accomplish this result he arrests the movement of the steering wheel after the same is moved sufiiciently to open the valve 36. The lever 60, operated by the power element i6 and operating as a lever of the first class, then rotates about its connection with the link 66; and this operation serves to reverse the direction of movement of the valve member 36 to lap the valve, that is cover the upper end of the duct 42. The movement of the power element i8 and the wheels ii connected thereto is then arrested when the system is in equilibrium. To resume the movement of the steering wheels II, the driver resumes the movement of the steering wheel to again crack the valve to again energize the motor 26.

The above described operation of the steering mechanism constituting my invention concerned the steering movement of the front wheels in one direction, however, it will be apparent from an inspection of Figure 2 of the drawings that the operation of said mechanism to effect thesteering movement of said wheels in the opposite direction is just the reverse of the above described I operation. In other words, if the steering wheel is rotated to efiect a clockwise rotation of the cranks 56 and B and pitman arm l2, then the valve 36 is moved to the left, Figure 2, to uncover the duct 46; and this operation results in an energization of the motor 26 to move the drag link Ill to the left.

There is thus provided a combined power and manually operated steering mechanism for ef fecting the steering operation of the front wheels of .an automotive vehicle. With the mechanism of my invention, by virtue of the operation of the springs 64 and 10, most of the steering operations are performed solely by the physical effort of the driver. However when the steering becomes diirlcult, that is when a substantial force is necessary to turn the front wheels, then the power means of my invention is brought into play to either of itself or aided by the physical effort of the driver, effect the steering operation. The pressure differential operated motor of my 6 able valve member and the pitman arm said linkage means serving to efiect a follow-up to la'p operation of the valve and to transmit the power load from the power element to the pitman arm. 3. In an automotive vehicle provided with a steering wheel, dirigible wheels and means, includinga drag link, for operating said wheels to steer the vehicle, manually and power operated means for moving said drag link comprising a pressure diiferential operated motor including a casing and a power element, valve means, including a movable valve member, for controlling the operation of said motor and force transmitting means interconnecting the drag link the invention is controlled by a follow-up valve and g the aforementioned springs 64 and 10 provide a so-called feel means to advise the driver when the power means is brought into operation.

Although the invention has been described in connection with a certain specific embodiment of my invention the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is therefore to be limited only as indicated by the appended claims.

I claim:

1. In. an automotive vehicle provided with a steering wheel, dirigible wheels and means for operating said wheels to steer the vehicle said means including a drag link and manually and power operated means for moving said drag link comprising a pressure differential operated motor including a casing and a power element, followup valve means, including a movable valve member, for controlling the operation of said motor and force transmitting means interconnecting the drag link, the movable valve member, the power element and the steering wheel, said force transmitting means including a plurality of cranks and a pitman arm and further including two springs interconnecting said cranks and pitman armone or the-other of said springs being operative by either resisting expansion or being expanded, to make possible respectively, a manual 'operation'of the first mentioned means or a power operation thereof.

2. In an automotive vehicle provided with a steering wheel, dirigible wheels and means, including a drag link, for operating said wheels to steer the vehicle, manually and power operated means for moving said drag link comprising a pressure differential operated motor including a casing and a. power element, valve means, in-- cluding a movable valve member, for controlling the operation of said motor and force transmitting means interconnecting the drag link, the

movable valve member, the power element and the steering wheel, said force transmitting means including a shaft rotated by means operated by the steering wheel, two cranks each keyed to said shaft, a pitman arm, means, including two springs, connecting said pitman arm with the two cranks, and linkage means interconnecting one of said cranks, the power element, the movincluding a shaft rotated by means operated by I the steering wheel, two cranks each keyed to said shaft, a pitman arm pivotally connected to the drag link, means, including two springs interconnecting said pitman arm with the two cranks, and linkage means interconnecting one of said cranks, the power element, the movable valve member and the pitman arm the parts of said force transmitting means being so constructed and arranged and so operative that with a succession of movements of the steering wheel there results, by virtue of a follow-up to lap operation of the valve means, a succession of operations of the motor to effect a steering movement of the dirigible wheels. I

4. In an automotive vehicle provided with a steering wheel, two dirigible wheels, and means, including a drag link, for operating said wheels to eifect the steering of the vehicle, power and manually operated means for bodily moving said drag link including a double-acting pressure differential operated motor, valve means for controlling the operation of said motor and force transmitting means interconnecting the valve means, the power element of the motor, the aforecranks keyed to said shaft, means,'including a.

spring, interconnecting one of said cranks with the pitman arm, means, including a spring, in terconnecting the other of said cranks with the pitman arm and means interconnecting oneof said cranks, a part of the valve'means, the pitman arm and the power element of the motor, the parts of said force transmitting means being so constructed and arranged and so operative that with a succession of movements of the steering wheel there results, by virtue of a follow-up to lap action of the valve mechanism, a succession of operations of the motor to. effect a steering movement of the dirigible wheels.

. HENRY 'D.- HUKILL.

- naraaancas crran file of this. patent:

' UNITED STATES PATENTS Number Name Date 2,051,816- Bragg Aug. 25, 1936 FOREIGN PATENTS v Number Country Date 747,960 France Apr. 4, 1933 

